If there is a new to request a new IP-address:
There is no utility with a Windows GUI ( like the Windows95/98 "winipcfg" )

The Window2000 Help shows under "DHCP"
the usage of IPCONFIG to renew an
IP-address:

You need to open a Command-Prompt windows and enter: ipconfig
/renew :

Luckily there is only a limited need to run this command
manually, since a Windows2000 system
keeps monitoring the network for a DHCP-server and will use it.( for example: my Windows2000 system
had booted using the IP-Autoconfiguration, using
an 169.254.x.x IP-address, but when I then started up an
NT4-server with DHCP-server,
it used the DHCP-server to request an IP-address without any
action from myself ).